#define _CRT_SECURE_NO_WARNINGS 1
#include"vector.h"
class Solution {
public:
    bool isPalindrome(string s)
    {

        string s1; 
        string s2;
        for (int i = 0; i < s.size(); ++i)
        {
            s[i] = tolower(s[i]);
            if ((s[i] <= 'z' && s[i] >= 'a') || (s[i] <= '9' && s[i] >= '0'))
            {
                s1 += s[i];
            }
        }


        s2 = s1;
        reverse(s1.begin(), s1.end());
        return s1 == s2;

    }
};